1) Teachers in a co-ed school said, it can be distracting for boys and girls to be in the same class. As they get older, they are distracted from focusing on their studies. Other problems tend to crop up as well.
2) Some teachers felt that the students exhibit extreme amounts of chutzpah, perhaps picked up from modern media. I think that chutzpah is a generational problem in all schools – modern or yeshivish.
3) Some teachers felt that there is less supervision at home in regards to current technological usage, which, in my view, is hurting both our community and the secular world. I know that technology has, in many instances, greatly contributed to societal advancement, but it has also created havoc in our lives. To be sure, some families are attempting to exert control over their children in this area, while other families are having a hard time limiting their children to viewing only appropriate subject matters.
Yeshivish schools can definitely learn from the high-caliber education that is sometimes found in Modern Orthodox schools. For their part, the latter schools can learn some things from the yeshivish schools, i.e., certain hashkafic values. Unfortunately, one thing all schools have in common is the troubling issue of bullying – a problem that needs to be addressed by everyone.
The reason why some of the more Modern Orthodox schools can be problematic for yeshivish families is because of a difference in values. Problems can arise when more yeshivish families may not want their children exposed to certain hadrachos acceptable to the Modern Orthodox family.
Your points are well taken. Thank you and hatzlachah!